Remote-controlled underwater buoy

ABSTRACT

In accordance with an illustrative embodiment of the present invention, a remote-controlled, immersed buoy that makes it possible to connect an object placed on the ocean floor to the surface by means of a wire rope comprises a body member kept in the immersed position by a latching assembly capable of being freed by a beacon upon the reception of an acoustic signal. A wire rope attached to an anchoring element winds on a drum as the buoy is raised. A removable electric motor is used to wind the wire rope on its drum to bring the buoy to the immersed position.

Elnited States Fatent [191 Houot June 17, 1975 [75] Inventor: Georges Sylvain l-louot, La Garde,

France [73] Assignee: Schlumberger Technology Corporation, New York, NY

221 Filed: Jan. 9, 1974 21 Appl.No.:432,l26

[30] Foreign Application Priority Data 3,402,687 9/1968 Tsuji 9/8 R 3,415,317 12/1968 Drivet 166/.6 3,638,722 2/1972 Talley 166/.5 3,722,014 3/1973 Hill et a1... 9/8 R 3,793,685 2/1974 Knecht 114/230 Primary Examiner-Trygve M. Blix Assistant Examiner-Gregory W. OConnor Attorney, Agent, or Firm-David L. Moseley; William R. Sherman; Stewart F. Moore [5 7 ABSTRACT In accordance with an illustrative embodiment of the present invention, a remote-controlled, immersed buoy that makes it possible to connect an object placed on the ocean floor to the surface by means of a wire rope comprises a body member kept in the immersed position by a latching assembly capable of being freed by a beacon upon the reception of an acoustic signal. A wire rope attached to an anchoring element winds on a drum as the buoy is raised. A removable electric motor is used to wind the wire rope on its drum to bring the buoy to the immersed position.

17 Claims, 3 Drawing Figures REMOTE-CONTROLLED UNDERWATER BUOY This invention relates generally to a remotecontrolled immersed buoy, and particularly a buoy that makes it possible to connect an object placed on the ocean floor with the surface by means of a wire rope or the like.

There are prior-art buoys of the type which are normally immersed and which can be raised to the surface in response to a remote-control signal. This type of buoy comprises a body member connected by a cable to an anchoring element lying on the sea bottom, and a thrust device bringing the body member to the surface under the action of a release mechanism remotecontrolled from the surface. When the buoy floats, a wire rope is used for linking the anchoring element with the surface. An embodiment of such an arrangement is described, for example, in US. Pat. No. 3,487,486.

This type of buoy has many applications. Offshore drilling operations require the installation of wellheads, valves, separators, and so forth, on the ocean bottom. In order to reach these installations for maintenance or the like, it is necessary to provide guide cables between them and the surface, so as to make it possible to lower the necessary maintenance equipment down to the wellhead. By means of these immersed buoys, it is possible to keep cables attached permanently to the wellhead on the sea floor and to bring one end of the cable up to the surface when desired.

In oceanography, it is becoming increasingly common practice to set up recorders on or near the ocean floor for temperature, pressure, salinity or pH recordings, and to collect recorded data at regular intervals. This makes it necessary to periodically retrieve these recorders in order to collect the recorded information and to recondition these instruments. An immersed buoy allows these operations to be carried out easily. After these retrieval operations, the equipment must be put back in the same position it occupied previously.

In certain prior'art systems, the cable is placed in a compartment of the body member and unwinds from this compartment when the buoy is raised. On important feature of this system is that the cable does not lie on the bottom and therefore cannot become tangled or snarled on jagged rocks or other objects. This type of buoy however has several drawbacks. Firstly, the cable is generally exposed to corrosion by the sea water which penetrates into the compartment. This is troublesome because the replacement of a deteriorated cable generally involves underwater operations, particularly when the anchoring element is secured as in the case of a wellhead. Moreover, this type of buoy must be allowed to sink to the ocean bottom and therefore cannot be placed with great accuracy, or must be placed by a diver if a predetermined location is involved. A fixed immersion location is of particular value for oceanographic measurements which must be made preferably at specific points, as well as for locating wellheads which are generally surrounded by all kinds of equipment in which a buoy placed by sinking can get caught.

It is an object of this invention to provide a new and improved remote-controlled immersed buoy having a connection cable that is particularly well protected from any deterioration.

Another object of the invention is to provide a new and improved remote-controlled immersed buoy which can be placed easily in an exact underwater location.

These and other objects are attained in accordance with the concepts of the present invention through the provision of a remote-controlled immersed buoy comprising a body member connected by a wire rope to an anchoring element placed on the sea floor, and a thrust device for driving the body member to the surface under the action of a remote-controlled release mechanism. The wire rope runs over a drum mounted in the body member inside an oil-filled chamber. Drum driving means are provided to wind the wire rope on the drum and to bring the body member to a given immersed position with respect to the anchoring point. The driving means comprise a mechanical transmission rotatingly connected to the drum with one end projecting beyond the body member for coupling to a removable electric motor fixed temporarily on the body member, by means of electromagnets for example. When the buoy is in the immersed position, the electromagnets can be. freed, thereby disengaging the electric motor which can be brought up to the surface by means of its electric cable.

The buoy according to the principles of the present invention also includes a latching assembly for securing the body member on a head fixed to the anchoring element. This latching assembly includes latching components adapted to engage the head, unlatching means releasing the latching components, and control means, preferably comprised of a pyrotechnical cylinder, for actuating the unlatching means in response to an electric signal from the remote-controlled release mechanism. The thrust device includes a ballast which is normally filled with water and in which floats are placed in order to give permanent buoyancy to the apparatus. Compressed gas cylinders whose opening is controlled by the release mechanism make it possible to fill the ballast with gas. After the reception of the release signal, the buoy comes up to the surface by simple buoyancy while unwinding its wire rope. To return the buoy to its immersed position, the wire rope is wound on the drum by means of the removable electric motor.

For a better understanding of the invention together with further objects and advantages thereof, reference may be made to the following description and to the drawings in which:

FIG. 1 is a perspective view of a buoy according to the invention shown floating on the surface, this view being cut away partially to show the internal components;

FIG. 2 is a longitudinal section of the buoy of FIG. 1 shown in the immersed position; and

FIG. 3 is a section along the line 33 of FIG. 2, the buoy being shown during lowering to its immersed position.

Referring initially to FIG. 1, a buoy 11 according to the invention is shown floating on the surface of the sea and is connected by a wire rope 12 to an anchoring element 13 lying on the ocean floor 14. The anchoring element 13 shown here in the form of a deadman, can be an underwater wellhead. The buoy 11 comprises a radar reflector 15 mounted on a mast 16 itself attached to a body member 17. The mast 16 can be surrounded by floats 20 which cooperate with other floats described hereinbelow to give the buoy 11 a permanent positive buoyancy of a predetermined value.

The body member 17, shown in greater detail in FIGS. 2 and 3, comprises a frame, metallic for example,

made of square-section tubing elements such as 21. The frame comprises a substantially rectangular upper part 22 whose sides and upper face are closed by a thin plate 23. This upper part 22 of the body member 17 constitutes a ballast open on its lower face and in which are placed several rows of spherical floats 24. This ballast also includes, on one of its sides, a U tube 26 allowing the air to escape when the buoy is placed in the water.

The lower part of the frame forms two lateral rectangular cages 30 and 31 (FIG. 3) in which floats 32 are also placed. The floats 20, 24 and 32 give the buoy a permanent buoyancy of the order of one hundred or so kilograms.

Between the two lateral cages 30 and 31 is placed a closed octogonal chamber 34 limited by a thin plate 35 welded on the square tubing. This chamber, filled with oil by means of filler and drain plugs, such as 36, is kept at ambient pressure by a tube 37 (FIG. 2) which connects the lower part of the chamber with the outside. Within the chamber, on a plate 40 integral with the frame, is fixed a substantially triangular support 41 at the top of which is mounted a reducer 42 having an output shaft 43 and an input shaft 44. On the output shaft 43 is fixed a drum 45 on which the wire rope 12 is wound.

The reducer 42 is an element of a transmission system which connects the drum 45 to a point located at the upper part of the body member 17. The input shaft 44 of the reducer carries a sprocket on which engages a chain 51 which also runs over a second sprocket 52 located at the lower part of the chamber. The second sprocket 52 is fixed to a horizontal shaft 53 mounted rotatively in a casing 54 fixed through a partition 55. Watertightness between the casing 54 and the horizontal shaft 53 is provided by lip seals (not shown) allowing a watertight passage through the partition 55. Owing to its position at the bottom of the chamber 34, poor Watertightness in this passage will result only in filling with water the lower part of this chamber, the winch and the reducer running in oil, even in this unfavorable case. The outer end of the horizontal shaft 53 is equipped with a bevel gear 56 meshing with a second bevel gear 57 fixed on a vertical shaft 58 which extends to the upper part of the body member through a tube 59 and terminates at the top by a nylon-toothed coupling 60. This coupling makes it possible to establish a connection with the output shaft of a motor 61 simply by fitting in the motor. The vertical shaft 58 is driven upward by a spring 62 which uncouples the bevel gear 57 from the bevel gear 56 when the motor 61 is disengaged from the body member. On the other hand, when the motor 61 is maintained against the body member as shown in FIG. 3, its output shaft drives the vertical shaft 58 downward and engages the gears 56 and 57. This makes it possible to minimize friction which opposes the movement of the drum 45 when the buoy is raised to the surface.

The motor 61 is fixed on a support 63 carrying, on either side of the motor, two electromagnets 64 which are applied, when they are supplied with current, to soft iron plates 65 attached to the body member 17. To prevent water pressure from keeping the electromagnets 64 applied on their soft iron plates 65, a gap is provided, for example by means of a nylon thread arranged in loops between each plate 65 and the corresponding electromagnet 64. A multiconductor electric cable 66,

which extends up to the surface, allows the supply of the motor 61 and of the electromagnets 64. The cable 66 is equipped with floats 67 giving it a constant slight upward tension during the lowering of the buoy.

At the exit of the drum 45, the wire rope 12 runs over a guide pulley 70 and then goes through a stuffing box 71 fixed through a lower partition 72 of the chamber 34. The stuffing box 71 is equipped with a packing 73 (FIG. 2). The guide pulley 70 is rotateably mounted on uprights 74 fixed to a crown 75 itself mounted rotateably around the stuffing box 71 by means of a bearing 76. The pulley 70 can thus move around a vertical axis ensuring a regular winding of the wire rope 12 on the drum 45. The end of the wire rope 12 is attached to a spherical head 77 fixed to the anchoring element 13.

The bottom of the buoy includes a latching assembly capable of engaging with the spherical head 77. This latching assembly includes a support crown 80 attached to the partition 72 and in which is slidingly mounted a skirt 81 driven downward by a spring 82 compressed between the partition 72 and the upper face of the skirt 81. A stop 83 limits the downward movement of the skirt 81 with respect to the crown 80. At the upper part of the skirt 81 are placed drive means consisting of a pyrotechnical gas generator 84 and a cylinder 85 in which is slidingly mounted an annular piston 86.

The pyrotechnical gas generator 84 consists of an annular chamber 87 communicating with the upper part of the cylinder 85 through openings 90 in which are placed cartridges 91 fired by an electric signal. Electric conductors 92, going through the top of the gas generator in a sealed manner, are used for this firing.

At the lower part of the skirt 81, which ends in a cone 93 facilitating the introduction on the head 77, are mounted latching elements or tumblers 94 capable of rotating around axes 95. The lower part of the tumblers 94 has a section of greater thickness so as to bear under the head 77 and block the upward movement of the skirt 81 with respect to this head.

A locking and release sleeve 96 is mounted slidingly in an intermediate part of the skirt 81 so as to be able to move between a high position where it locks the tumblers 94 (FIG. 2) and a low position where it releases these tumblers (FIG. 3). The sleeve 96 has a tapered outer surface 97 and is extended upward by flexible fingers 100. Each flexible finger 100 comprises at its upper part a head 101 which engages, in the low position of the sleeve 96, under a boss 102 made on the inner surface of the skirt 81 (FIG. 3) and, in the high position (FIG. 2), in a groove 103 cut in the outer surface of the piston 86. In the high release position of the sleeve 96, the tumblers 94 cannot move away from the spherical head 77. On the other hand, in the low position, the tapered outer surface 97 allows the tumblers to rotate around their axes 95 so that their lower part can move away from the head 77.

At the upper part and on the side of the body member is fixed an acoustic beacon 104 of a conventional type adapted to produce an electric signal upon reception of a coded acoustic signal. The beacon 104, supplied by a built-in electric energy source, is connected via an insulated electric conductor 105 to the cartridges 91 of the gas generator 84. The buoy is moreover equipped with compressed air bottles 106 communicating, through an explosive plug 107 and a conduit 108, with the upper part of the ballast 22. The explosive plugs 107 are also connected via an electric conductor 110 to the acoustic beacon 104. The heads of the cylinder 106 are placed under side projections of the ballast 42 which recover the air in case of leaks from the plugs 107.

To consider the operation of the system, let us first assume the buoy 11 to be in the immersed position latched on the spherical head 77 as shown in FIG. 2. The wire rope 12 is wound on the drum 45 and the locking and release sleeve 96 is in the high position thereby locking the tumblers 94 on the head 77. The acoustic beacon 104 is in the standby mode and the buoy maintains a substantially vertical position owing to the buoyancy of the floats 20, 24 and 32. The upper ballast 22 is filled with water.

On reception of a coded acoustic signal, transmitted by a service vessel, the acoustic beacon 104 is energized and sends an electric signal to the gas generator 84 and to the explosive plugs 107. The compressed air from the bottles 106 drives the water out of the ballast, thereby greatly increasing the buoyancy of the buoy, by 500 kg for example. The generator 84 sends gas under pressure into the cylinder 85 and the piston 86 moves downward, driving the release sleeve 96. This sleeve bears on top of the spherical head 77, thereby freeing the tumblers 94 so that their lower parts can move and clear this spherical head. Under the effect of buoyancy, the buoy has a tendency to move upward. If the separation does not take place, the sleeve 96 reaches the end of its travel and bears on the spherical head 77 thereby pushing the buoy upward. As the buoy 11 moves toward the surface, the wire rope 12 unwinds from the drum 45. v

Upon reaching the surface, the buoy 11 floats, with the mast 16 and the radar reflector being clearly emerged from the water, thereby allowing easy detection of the buoy either by radar or by sight. The service vessel can then recover the unit and unwind the wire rope 12 completely to use it as a guide cable if necessary for the contemplated operations, after having drained any oil and water which may have replaced the volume of the cable in the octogonal chamber 34 during the raising of the buoy.

During various operations, for example involving specific work on a wellhead or the retrieval of oceanographic recordings, the buoy 11 is prepared prior to its return to the ocean floor in the following manner. The electric energy source of the beacon, the gas generator 84, the compressed air bottles 106 and the explosive plugs 107 are charged or replaced. Then, the upper end of the wire rope is wound on its drum, the chamber 34 is filled with oil and the latching elements are placed in the position shown in FIG. 3, i.e. the piston 86 in the high position and the release sleeve 96 in the low position, the heads 101 of the flexible fingers 100 being engaged under the boss 102.

To lower the buoy 11 to its immersed position, the electric motor 61 is installed, the electromagnets 64 are supplied and the assembly is placed in the water. The buoy then has the position shown in FIG. 1. The electric motor 61 is then energized and drives the drum 45 through a vertical shaft 58, bevel gears 56 and 57, the shaft 53, the chain 51 and the reducer 42, thereby winding the wire rope 12 which takes the assembly down to the bottom. Upon reaching the bottom, the skirt 81, guided by the cone 93, fits over the spherical head 77 which engages under the tumblers 94 and drives the release sleeve 96 upward. The heads 101 of the flexible fingers 100 clear the boss 102 and engage in the groove 103 of the piston 86. The sleeve 96 is then in the high position where it locks the tumblers 94. The motor 61 continues to wind the wire rope and drives the assembly downward while compressing the spring 82. The increase in the electric power required by the motor 61 opens the circuit-breaker located aboard the vessel. The supply of the electromagnets 64 is then cut and the electric motor 61 is recovered by pulling on the electric cable 66. The latching system remains locked on the spherical head 77 as long as the cylinder is not actuated.

In the apparatus hereinabove described, it will be noted that during the waiting periods in the immersed position, the wire rope 12 is wound on the drum 45. This wire rope consequently is not in danger of entanglement and, since it is placed in an oil-filled chamber, it is protected against corrosion, electrolytic effects and undersea animals. Except for the anchoring element, the spherical head and the wire rope itself, all the equipment can be brought to the surface, and consequently, maintained and replaced easily. This indicates the importance of the care given to the maintenance of the rope which, with the anchoring element, remains constantly under water.

The apparatus hereinabove described can of course involve many variations and modifications both 'as regards the choice of the materials used, for the frame for example, as well as the design of the latching and locking assembly or of any other component. Thus it is the aim of the appended claims to cover all changes or modifications falling within the true spirit and scope of the present invention.

I claim:

1. A remotely controlled buoy apparatus adapted to be submerged below the surface of a body of water, comprising: a body having thrust means for applying an upward force thereto; an anchoring element; latching means for maintaining said body in a predetermined immersed position relative to said anchoring element; remotely controlled means for releasing said latching means to allow said body to be moved upwardly to the surface of the water by said thrust means; a drum rotatably mounted and enclosed within said body; a line wound on said drum and having one end extending from said body and fixed to said anchoring element so as to unwind from said drum when said body is moving upwardly; a motor releasably attached to the exterior of said body; and transmission means connected between said motor and said drum for enabling said motor to wind said line on said drum, thereby moving said body downwardly within said water to the predetermined immersed position therein.

2. The apparatus of claim 1 further including oilfilled chamber means in said body for enclosing said drum.

3. The apparatus of claim 2 further including a stuffing box means sealingly engaging said line as it leaves said chamber means.

4. The apparatus of claim 3 further including means for maintaining the oil in said chamber means at substantially the same pressure as the pressure of the water outside of said body.

5. The apparatus of claim 4 wherein said chamber means contains line guiding means located between said drum and the exit point of said line from said chamber means to allow regular winding of said line on said drum.

6. The apparatus of claim 1 wherein said transmission means includes a drive train having one end connected to said drum and the other end extending beyond said body and adapted to be coupled with said motor.

7. The apparatus of claim 6 wherein said other end of said drive train extends beyond the upper side of said body.

8. The apparatus of claim 7 further including chamber means for enclosing said drum within said body, and wherein said drive train extends through a wall of said chamber means in a sealed manner at a point located at a lower portion of said chamber means.

9. The apparatus of claim 8 further including means for disengaging said drive train when said other end thereof is uncoupled from said motor.

10. The apparatus of claim 6 further including means remotely operable from the surface of the water for releasably attaching said motor to said body.

11. The apparatus of claim 10 wherein said motor is an .electric device supplied from the surface through an electric cable equipped with floats.

12. The apparatus of claim 1 further comprising a head on said anchoring element, said latching means being cooperable with said head for securing said body thereto.

13. The apparatus of claim 12 wherein said latching means comprises latching components adapted to engage said head, said releasing means including means for locking and releasing said latching components.

14. The apparatus of claim 13 wherein said releasing means further comprises control means for actuating said releasing and locking means.

15. The apparatus of claim 14 wherein said control means comprises pressure responsive means for actuating said releasing and locking means, and a gas generator sensitive to a control signal for applying pressure to said pressure responsive means.

16. The apparatus of claim 15 wherein said releasing means comprises means for separating said head from said latching components.

17. The apparatus of claim 16 wherein said thrust means comprises floats giving permanent buoyancy to said buoy apparatus and a reservoir adapted to be filled with gas to furnish additional buoyancy during the raising of said buoy apparatus to the surface of a body of water. 

1. A remotely controlled buoy apparatus adapted to be submerged below the surface of a body of water, comprising: a body having thrust means for applying an upward force thereto; an anchoring element; latching means for maintaining said body in a predetermined immersed position relative to said anchoring element; remotely controlled means for releasing said latching means to allow said body to be moved upwardly to the surface of the water by said thrust means; a drum rotatably mounted and enclosed within said body; a line wound on said drum and having one end extending from said body and fixed to said anchoring element so as to unwind from said drum when said body is moving upwardly; a motor releasably attached to the exterior of said body; and transmission means connected between said motor and said drum for enabling said motor to wind said line on said drum, thereby moving said body downwardly within said water to the predetermined immersed position therein.
 2. The apparatus of claim 1 further including oil-filled chamber means in said body for enclosing said drum.
 3. The apparatus of claim 2 further including a stuffing box means sealingly engaging said line as it leaves said chamber means.
 4. The apparatus of claim 3 further including means for maintaining the oil in said chamber means at substantially the same pressure as the pressure of the water outside of said body.
 5. The apparatus of claim 4 wherein said chamber means contains line guiding means located between said drum and the exit point of said line from said chamber means to allow regular winding of said line on said drum.
 6. The apparatus of claim 1 wherein said transmission means includes a drive train having one end connected to said drum and the other end extending beyond said body and adapted to be coupled with said motor.
 7. The apparatus of claim 6 wherein said other end of said drive train extends beyond the upper side of said body.
 8. The apparatus of claim 7 further including chamber means for enclosing said drum within said body, and wherein said drive train extends through a wall of said chamber means in a sealed manner at a point located at a lower portion of said chamber means.
 9. The apparatus of claim 8 further including means for disengaging said drive train when said other end thereof is uncoupled from said motor.
 10. The apparatus of claim 6 further including means remotely operable from the surface of the water for releasably attaching said motor to said body.
 11. The apparatus of claim 10 wherein said motor is an electric device supplied from the surface through an electric cable equipped with floats.
 12. The apparatus of claim 1 further comprising a head on said anchoring element, said latching means being cooperable with said head for securing said body thereto.
 13. The apparatus of claim 12 wherein said latching means comprises latching components adapted to engage said head, said releasing means including means for locking and releasing said latching components.
 14. The apparatus of claim 13 wherein said releasing means further comprises control means for actuating said releasing and locking means.
 15. The apparatus of claim 14 wherein said control means comprises pressure responsive means for actuating said releasing and locking means, and a gas generator sensitive to a control signal for applying pressure to said pressure responsive means.
 16. The apparatus of claim 15 wherein said releasing means comprises means for separating said head from said latching components.
 17. The apparatus of claim 16 wherein said thrust means comprises floats giving permanent buoyancy to said buoy apparatus and a reservoir adapted to be fillEd with gas to furnish additional buoyancy during the raising of said buoy apparatus to the surface of a body of water. 